Clinical context
Cataract surgery outcomes are not defined by best-corrected visual acuity alone. Refractive accuracy, vision at different distances, spectacle dependence, contrast sensitivity, dysphotopsia and procedural safety all matter. Corneal and macular status, capsular support, cataract density and IOL calculation also shape the final result. A statistically convincing average therefore still has to be interpreted against the characteristics of an individual eye.
What was studied
Without capsular support, secondary IOL choice involves different fixation tradeoffs. This meta-analysis compared sutureless scleral-fixated Carlevale and retropupillary Artisan iris-claw lenses. PubMed, Embase and Cochrane Library were searched through March 2025. Five studies included 631 eyes: 229 Carlevale and 402 iris-claw. Mean age was 70.1 years and follow-up ranged from 1.3 to 11.5 months.
How the evidence was produced
A meta-analysis combines several studies and can increase the precision of an overall estimate. Its conclusion still depends on the quality of the component studies, comparability of interventions and endpoints, statistical heterogeneity and publication bias. The pooled effect should be read with its confidence interval, sensitivity analyses and the reasons results differed across studies.
How to interpret the result
Both approaches can restore vision, but similar mean acuity does not make them interchangeable. Incision choice affects astigmatism and predictability, while Carlevale takes longer and showed a systematic myopic shift. Selection should reflect iris and scleral status, vitrectomy needs, surgeon expertise and refractive planning.
The result should be understood as an estimate for the population studied, not a promise of an individual outcome. Statistical and clinical significance, absolute and relative effects, and prespecified and exploratory analyses should be distinguished. When several endpoints or subgroups are reported, the prespecified primary endpoint for which the study was designed usually provides the most reliable inference.
Clinical applicability
This evidence is most useful as a basis for preoperative discussion and surgical planning. It helps identify which outcomes should be measured and which trade-offs should be explained to patients. The average effect should not be generalized to every IOL, technique or patient without checking eligibility criteria, surgeon experience, biometry, ocular comorbidity and duration of follow-up.
Limitations
Only five mostly nonrandomized studies with short follow-up were available. Indications, incisions and techniques varied, and heterogeneity was high for several outcomes. Rare late complications remain uncertain. Verify bias assessments, dislocation definitions, causes of aphakia, lens models, vitrectomy, attrition, sensitivity analyses and incision subgroups in the source.
Beyond the limitations acknowledged by the authors, confidence is affected by sample size, follow-up duration, missing data, choice of comparator and relevance of the outcomes to routine care. Uncommon complications may remain undetected even in a well-conducted study. External validity is reduced when participants, equipment or investigator expertise differ substantially from everyday settings.
What to verify in the source
In the full paper, verify the protocol, eligibility criteria, baseline group characteristics, primary endpoint definition, confidence intervals, adverse events and losses to follow-up. Funding, conflicts of interest, trial registration and consistency between the published analysis and the original plan deserve separate attention. The DOI or source link below provides access to the primary publication for this check.